Merge branch 'stable' into v2

Add support of proxy protocol

.github/workflows/ci.yaml

@@ -93,6 +93,9 @@ jobs:
     name: Docker
     runs-on: ubuntu-latest
     timeout-minutes: 20
+    permissions:
+      contents: read
+      packages: write
     steps:
       - name: Checkout
         uses: actions/checkout@v6
@@ -103,9 +106,16 @@ jobs:
         id: meta
         uses: docker/metadata-action@v5
         with:
-          images: nineseconds/mtg
+          images: |
+            nineseconds/mtg
+            ghcr.io/${{ github.repository }}
           tags: |
             type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=semver,pattern={{major}}
+            type=raw,value=latest,enable={{is_default_branch}}
+            type=raw,value=master,enable=${{ github.ref == 'refs/heads/master' }}
+            type=raw,value=stable,enable=${{ github.ref == 'refs/heads/stable' }}
 
       - name: Setup QEMU
         uses: docker/setup-qemu-action@v3
@@ -128,6 +138,14 @@ jobs:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_PASSWORD }}
 
+      - name: Login to GitHub Container Registry
+        if: github.event_name != 'pull_request'
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
       - name: Build and push
         uses: docker/build-push-action@v2
         with:

.mise.toml

@@ -1,5 +1,10 @@
 [tools]
+"go:golang.org/x/pkgsite/cmd/pkgsite" = "latest"
+"go:golang.org/x/tools/gopls" = "latest"
+"go:mvdan.cc/gofumpt" = "latest"
 go = "latest"
+golangci-lint = "latest"
+goreleaser = "latest"
 
 [vars]
 fuzzflags = "-fuzztime=120s"
@@ -19,7 +24,6 @@ run = [
 
 [tasks.lint]
 description = "Run linter"
-tools.golangci-lint = "latest"
 run = "golangci-lint run"
 
 [tasks.test]
@@ -75,7 +79,6 @@ go build \
 
 [tasks.release]
 description = "Create release tarballs"
-tools.goreleaser = "latest"
 sources = ["**/*.go", "go.mod", "go.sum", ".goreleaser.yml"]
 run = [
     "goreleaser --snapshot --clean",
@@ -90,11 +93,9 @@ run = "docker buildx build --pull -t mtg ."
 
 [tasks.docs]
 description = "Run doc server"
-tools."go:golang.org/x/pkgsite/cmd/pkgsite" = "latest"
 run = "pkgsite -http 0.0.0.0:10000"
 
 [tasks.fmt]
 description = "Reformat source code"
-tools.gofumpt = "latest"
 sources = ["**/*.go"]
 run = "gofumpt -w --extra ."

README.md

@@ -10,6 +10,17 @@ Highly-opinionated (ex-bullshit-free) MTPROTO proxy for
 **If you use v1.0 or upgrade broke you proxy, please read the chapter
 [Version 2](#version-2)**
 
+If you want to have a proxy that _supports adtag_ (possibility to promote a
+channel with a special Telegram bot), I recommend to use
+[telemt](https://github.com/telemt/telemt) project. v1 of mtg supports it
+but I do not see any reasonable point of using it: adtag requires communication
+via a fragile set of middle proxies, requires complex setup that must expose
+a public IPs, has lower bandwidth and latency.
+
+mtg idea is simple: minimal unbloated proxy that can handle a reasonable scale
+~10-20k simultaneous connections, has no user management, but ticks all
+checkboxes related to its main intent: provide a way to use Telegram.
+
 ## Rationale
 
 There are several available proxies for Telegram MTPROTO available. Here
@@ -18,6 +29,7 @@ are the most notable:
 * [Official](https://github.com/TelegramMessenger/MTProxy)
 * [Python](https://github.com/alexbers/mtprotoproxy)
 * [Erlang](https://github.com/seriyps/mtproto_proxy)
+* [Telemt (Rust)](https://github.com/telemt/telemt)
 
 You can use any of these. They work great and all implementations have
 feature parity now. This includes support of adtag, replay attack
@@ -40,6 +52,12 @@ that probably matter.
   way of doing business I suppose. I think the only viable way is to
   have a proxy that can be restored anywhere easily.
 
+* **Supports proxy protocol v1/v2**
+
+  This makes integration with loadbalancers like HAProxy and ELB a first class
+  citizen by supporting their
+  [commuication protocols](https://www.haproxy.org/download/2.3/doc/proxy-protocol.txt).
+
 * **A single secret**
 
   I think that multiple secrets solve no problems and just complex
@@ -162,6 +180,12 @@ This project has several main branches
 
 ## Getting started
 
+### Download mise
+
+mtg uses [mise](https://mise.jdx.dev/) to maintain its development
+dependencies + replaces a make for building things. Please
+[install](https://mise.jdx.dev/getting-started.html) it first.
+
 ### Download a tool
 
 #### Download binaries
@@ -198,13 +222,14 @@ go install github.com/9seconds/mtg/v2@latest
 ```console
 git clone https://github.com/9seconds/mtg.git
 cd mtg
-make static
+mise install
+mise tasks run build
 ```
 
 or for the docker image:
 
 ```console
-make docker
+mise tasks run image
 ```
 
 ### Generate secret
@@ -275,7 +300,7 @@ Flags:
   -b, --tcp-buffer="4KB"               Size of TCP buffer to use.
   -i, --prefer-ip="prefer-ipv6"        IP preference. By default we prefer IPv6 with fallback to IPv4.
   -p, --domain-fronting-port=443       A port to access for domain fronting.
-  -n, --doh-ip=9.9.9.9                 IP address of DNS-over-HTTP to use.
+  -n, --doh-ip=1.1.1.1                 IP address of DNS-over-HTTP to use.
   -t, --timeout=10s                    Network timeout to use
   -a, --antireplay-cache-size="1MB"    A size of anti-replay cache to use.
 ```

events/event_stream.go

@@ -2,7 +2,7 @@ package events
 
 import (
 	"context"
-	"math/rand"
+	"math/rand/v2"
 	"runtime"
 
 	"github.com/9seconds/mtg/v2/mtglib"
@@ -64,7 +64,7 @@ func NewEventStream(observerFactories []ObserverFactory) EventStream {
 		chans:     make([]chan mtglib.Event, runtime.NumCPU()),
 	}
 
-	for i := 0; i < runtime.NumCPU(); i++ {
+	for i := range runtime.NumCPU() {
 		rv.chans[i] = make(chan mtglib.Event, 1)
 
 		if len(observerFactories) == 1 {

events/multi_observer.go

@@ -12,14 +12,11 @@ type multiObserver struct {
 
 func (m multiObserver) EventStart(evt mtglib.EventStart) {
 	wg := &sync.WaitGroup{}
-	wg.Add(len(m.observers))
 
 	for _, v := range m.observers {
-		go func(obs Observer) {
+		wg.Go(func() {
-			defer wg.Done()
+			v.EventStart(evt)
-
+		})
-			obs.EventStart(evt)
-		}(v)
 	}
 
 	wg.Wait()
@@ -27,14 +24,11 @@ func (m multiObserver) EventStart(evt mtglib.EventStart) {
 
 func (m multiObserver) EventConnectedToDC(evt mtglib.EventConnectedToDC) {
 	wg := &sync.WaitGroup{}
-	wg.Add(len(m.observers))
 
 	for _, v := range m.observers {
-		go func(obs Observer) {
+		wg.Go(func() {
-			defer wg.Done()
+			v.EventConnectedToDC(evt)
-
+		})
-			obs.EventConnectedToDC(evt)
-		}(v)
 	}
 
 	wg.Wait()
@@ -42,14 +36,11 @@ func (m multiObserver) EventConnectedToDC(evt mtglib.EventConnectedToDC) {
 
 func (m multiObserver) EventDomainFronting(evt mtglib.EventDomainFronting) {
 	wg := &sync.WaitGroup{}
-	wg.Add(len(m.observers))
 
 	for _, v := range m.observers {
-		go func(obs Observer) {
+		wg.Go(func() {
-			defer wg.Done()
+			v.EventDomainFronting(evt)
-
+		})
-			obs.EventDomainFronting(evt)
-		}(v)
 	}
 
 	wg.Wait()
@@ -57,14 +48,11 @@ func (m multiObserver) EventDomainFronting(evt mtglib.EventDomainFronting) {
 
 func (m multiObserver) EventTraffic(evt mtglib.EventTraffic) {
 	wg := &sync.WaitGroup{}
-	wg.Add(len(m.observers))
 
 	for _, v := range m.observers {
-		go func(obs Observer) {
+		wg.Go(func() {
-			defer wg.Done()
+			v.EventTraffic(evt)
-
+		})
-			obs.EventTraffic(evt)
-		}(v)
 	}
 
 	wg.Wait()
@@ -72,14 +60,11 @@ func (m multiObserver) EventTraffic(evt mtglib.EventTraffic) {
 
 func (m multiObserver) EventFinish(evt mtglib.EventFinish) {
 	wg := &sync.WaitGroup{}
-	wg.Add(len(m.observers))
 
 	for _, v := range m.observers {
-		go func(obs Observer) {
+		wg.Go(func() {
-			defer wg.Done()
+			v.EventFinish(evt)
-
+		})
-			obs.EventFinish(evt)
-		}(v)
 	}
 
 	wg.Wait()
@@ -87,14 +72,11 @@ func (m multiObserver) EventFinish(evt mtglib.EventFinish) {
 
 func (m multiObserver) EventConcurrencyLimited(evt mtglib.EventConcurrencyLimited) {
 	wg := &sync.WaitGroup{}
-	wg.Add(len(m.observers))
 
 	for _, v := range m.observers {
-		go func(obs Observer) {
+		wg.Go(func() {
-			defer wg.Done()
+			v.EventConcurrencyLimited(evt)
-
+		})
-			obs.EventConcurrencyLimited(evt)
-		}(v)
 	}
 
 	wg.Wait()
@@ -102,14 +84,11 @@ func (m multiObserver) EventConcurrencyLimited(evt mtglib.EventConcurrencyLimite
 
 func (m multiObserver) EventIPBlocklisted(evt mtglib.EventIPBlocklisted) {
 	wg := &sync.WaitGroup{}
-	wg.Add(len(m.observers))
 
 	for _, v := range m.observers {
-		go func(obs Observer) {
+		wg.Go(func() {
-			defer wg.Done()
+			v.EventIPBlocklisted(evt)
-
+		})
-			obs.EventIPBlocklisted(evt)
-		}(v)
 	}
 
 	wg.Wait()
@@ -117,14 +96,11 @@ func (m multiObserver) EventIPBlocklisted(evt mtglib.EventIPBlocklisted) {
 
 func (m multiObserver) EventReplayAttack(evt mtglib.EventReplayAttack) {
 	wg := &sync.WaitGroup{}
-	wg.Add(len(m.observers))
 
 	for _, v := range m.observers {
-		go func(obs Observer) {
+		wg.Go(func() {
-			defer wg.Done()
+			v.EventReplayAttack(evt)
-
+		})
-			obs.EventReplayAttack(evt)
-		}(v)
 	}
 
 	wg.Wait()
@@ -132,14 +108,11 @@ func (m multiObserver) EventReplayAttack(evt mtglib.EventReplayAttack) {
 
 func (m multiObserver) EventIPListSize(evt mtglib.EventIPListSize) {
 	wg := &sync.WaitGroup{}
-	wg.Add(len(m.observers))
 
 	for _, v := range m.observers {
-		go func(obs Observer) {
+		wg.Go(func() {
-			defer wg.Done()
+			v.EventIPListSize(evt)
-
+		})
-			obs.EventIPListSize(evt)
-		}(v)
 	}
 
 	wg.Wait()

example.config.toml

@@ -23,6 +23,15 @@ secret = "ee367a189aee18fa31c190054efd4a8e9573746f726167652e676f6f676c6561706973
 # Host:port pair to run proxy on.
 bind-to = "0.0.0.0:3128"
 
+# This defines what types of traffic mtg listens to. If you are not sure,
+# then definitely keep it disable. Enable it only and only if incoming traffic
+# is coming from some sort of load-balancer like HAProxy or ELB.
+# https://www.haproxy.org/download/2.3/doc/proxy-protocol.txt
+#
+# mtg uses a library that supports v1 and v2 versions of ProxyProtocol.
+# default value is false.
+# proxy-protocol-listener = false
+
 # Defines how many concurrent connections are allowed to this proxy.
 # All other incoming connections are going to be dropped.
 concurrency = 8192
@@ -71,6 +80,15 @@ tolerate-time-skewness = "5s"
 # Otherwise, chose a new DC.
 allow-fallback-on-unknown-dc = false
 
+# Telegram uses different DCs for different purposes. Unfortunately, most of
+# DCs are not public, and dependent on a location of the current user, so
+# mtg cannot know upfront about all of them, and how to access them. It has
+# a default list of DCs, including some CDN IPs, but it is possible that some
+# of them are not working for you. In this case, you can override them here.
+[[dc-overrides]]
+dc = 101
+ips = ["127.0.0.1:443"]
+
 # network defines different network-related settings
 [network]
 # please be aware that mtg needs to do some external requests. For
@@ -84,8 +102,8 @@ allow-fallback-on-unknown-dc = false
 # resolver of the operating system and uses DOH instead. This is a host
 # it has to access.
 #
-# By default we use Quad9.
+# By default we use Cloudflare.
-doh-ip = "9.9.9.9"
+doh-ip = "1.1.1.1"
 
 # mtg can work via proxies (for now, we support only socks5). Proxy
 # configuration is done via list. So, you can specify many proxies

go.mod

@@ -12,7 +12,6 @@ require (
 	github.com/jarcoal/httpmock v1.0.8
 	github.com/mccutchen/go-httpbin v1.1.1
 	github.com/panjf2000/ants/v2 v2.11.5
-	github.com/pelletier/go-toml v1.9.5
 	github.com/prometheus/client_golang v1.23.2
 	github.com/prometheus/common v0.67.5 // indirect
 	github.com/prometheus/procfs v0.19.2 // indirect
@@ -28,6 +27,8 @@ require (
 )
 
 require (
+	github.com/pelletier/go-toml/v2 v2.2.4
+	github.com/pires/go-proxyproto v0.11.0
 	github.com/txthinking/socks5 v0.0.0-20251011041537-5c31f201a10e
 	github.com/yl2chen/cidranger v1.0.2
 )
@@ -36,6 +37,7 @@ require (
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/klauspost/compress v1.18.3 // indirect
 	github.com/kr/text v0.2.0 // indirect
 	github.com/mattn/go-colorable v0.1.14 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
@@ -43,8 +45,10 @@ require (
 	github.com/patrickmn/go-cache v2.1.0+incompatible // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/prometheus/client_model v0.6.2 // indirect
+	github.com/rogpeppe/go-internal v1.14.1 // indirect
 	github.com/txthinking/runnergroup v0.0.0-20250224021307-5864ffeb65ae // indirect
 	go.yaml.in/yaml/v2 v2.4.3 // indirect
 	golang.org/x/sync v0.19.0 // indirect
+	golang.org/x/tools v0.41.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -30,8 +30,8 @@ github.com/hexops/gotextdiff v1.0.3 h1:gitA9+qJrrTCsiCl7+kh75nPqQt1cx4ZkudSTLoUq
 github.com/hexops/gotextdiff v1.0.3/go.mod h1:pSWU5MAI3yDq+fZBTazCSJysOMbxWL1BSow5/V2vxeg=
 github.com/jarcoal/httpmock v1.0.8 h1:8kI16SoO6LQKgPE7PvQuV+YuD/inwHd7fOOe2zMbo4k=
 github.com/jarcoal/httpmock v1.0.8/go.mod h1:ATjnClrvW/3tijVmpL/va5Z3aAyGvqU3gCT8nX0Txik=
-github.com/klauspost/compress v1.18.0 h1:c/Cqfb0r+Yi+JtIEq73FWXVkRonBlf0CRNYc8Zttxdo=
+github.com/klauspost/compress v1.18.3 h1:9PJRvfbmTabkOX8moIpXPbMMbYN60bWImDDU7L+/6zw=
-github.com/klauspost/compress v1.18.0/go.mod h1:2Pp+KzxcywXVXMr50+X0Q/Lsb43OQHYWRCY2AiWywWQ=
+github.com/klauspost/compress v1.18.3/go.mod h1:R0h/fSBs8DE4ENlcrlib3PsXS61voFxhIs2DeRhCvJ4=
 github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
 github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
@@ -55,8 +55,10 @@ github.com/panjf2000/ants/v2 v2.11.5 h1:a7LMnMEeux/ebqTux140tRiaqcFTV0q2bEHF03nl
 github.com/panjf2000/ants/v2 v2.11.5/go.mod h1:8u92CYMUc6gyvTIw8Ru7Mt7+/ESnJahz5EVtqfrilek=
 github.com/patrickmn/go-cache v2.1.0+incompatible h1:HRMgzkcYKYpi3C8ajMPV8OFXaaRUnok+kx1WdO15EQc=
 github.com/patrickmn/go-cache v2.1.0+incompatible/go.mod h1:3Qf8kWWT7OJRJbdiICTKqZju1ZixQ/KpMGzzAfe6+WQ=
-github.com/pelletier/go-toml v1.9.5 h1:4yBQzkHv+7BHq2PQUZF3Mx0IYxG7LsP222s7Agd3ve8=
+github.com/pelletier/go-toml/v2 v2.2.4 h1:mye9XuhQ6gvn5h28+VilKrrPoQVanw5PMw/TB0t5Ec4=
-github.com/pelletier/go-toml v1.9.5/go.mod h1:u1nR/EPcESfeI/szUZKdtJ0xRNbUoANCkoOuaOx1Y+c=
+github.com/pelletier/go-toml/v2 v2.2.4/go.mod h1:2gIqNv+qfxSVS7cM2xJQKtLSTLUE9V8t9Stt+h56mCY=
+github.com/pires/go-proxyproto v0.11.0 h1:gUQpS85X/VJMdUsYyEgyn59uLJvGqPhJV5YvG68wXH4=
+github.com/pires/go-proxyproto v0.11.0/go.mod h1:ZKAAyp3cgy5Y5Mo4n9AlScrkCZwUy0g3Jf+slqQVcuU=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
@@ -68,8 +70,8 @@ github.com/prometheus/common v0.67.5 h1:pIgK94WWlQt1WLwAC5j2ynLaBRDiinoAb86HZHTU
 github.com/prometheus/common v0.67.5/go.mod h1:SjE/0MzDEEAyrdr5Gqc6G+sXI67maCxzaT3A2+HqjUw=
 github.com/prometheus/procfs v0.19.2 h1:zUMhqEW66Ex7OXIiDkll3tl9a1ZdilUOd/F6ZXw4Vws=
 github.com/prometheus/procfs v0.19.2/go.mod h1:M0aotyiemPhBCM0z5w87kL22CxfcH05ZpYlu+b4J7mw=
-github.com/rogpeppe/go-internal v1.10.0 h1:TMyTOH3F/DB16zRVcYyreMH6GnZZrwQVAoYjRBZyWFQ=
+github.com/rogpeppe/go-internal v1.14.1 h1:UQB4HGPB6osV0SQTLymcB4TgvyWu6ZyliaW0tI/otEQ=
-github.com/rogpeppe/go-internal v1.10.0/go.mod h1:UQnix2H7Ngw/k4C5ijL5+65zddjncjaFoBhdsK/akog=
+github.com/rogpeppe/go-internal v1.14.1/go.mod h1:MaRKkUm5W0goXpeCfT7UZI6fk/L7L7so1lCWt35ZSgc=
 github.com/rs/xid v1.6.0/go.mod h1:7XoLgs4eV+QndskICGsho+ADou8ySMSjJKDIan90Nz0=
 github.com/rs/zerolog v1.34.0 h1:k43nTLIwcTVQAncfCw4KZ2VY6ukYoZaBPNOE8txlOeY=
 github.com/rs/zerolog v1.34.0/go.mod h1:bJsvje4Z08ROH4Nhs5iH600c3IkWhwp44iRc54W6wYQ=
@@ -106,8 +108,9 @@ golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5y
 golang.org/x/crypto v0.48.0 h1:/VRzVqiRSggnhY7gNRxPauEQ5Drw9haKdM0jqfcCFts=
 golang.org/x/crypto v0.48.0/go.mod h1:r0kV5h3qnFPlQnBSrULhlsRfryS2pmewsg+XfMgkVos=
 golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
-golang.org/x/mod v0.7.0 h1:LapD9S96VoQRhi/GrNTqeBJFrUjs5UHCAtTlgwA5oZA=
 golang.org/x/mod v0.7.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
+golang.org/x/mod v0.32.0 h1:9F4d3PHLljb6x//jOyokMv3eX+YDeepZSEo3mFJy93c=
+golang.org/x/mod v0.32.0/go.mod h1:SgipZ/3h2Ci89DlEtEXWUk/HteuRin+HHhN+WbNhguU=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
 golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
@@ -140,8 +143,9 @@ golang.org/x/text v0.4.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
-golang.org/x/tools v0.3.0 h1:SrNbZl6ECOS1qFzgTdQfWXZM9XBkiA6tkFrH9YSTPHM=
 golang.org/x/tools v0.3.0/go.mod h1:/rWhSS2+zyEVwoJf8YAX6L2f0ntZ7Kn/mGgAWcipA5k=
+golang.org/x/tools v0.41.0 h1:a9b8iMweWG+S0OBnlU36rzLp20z1Rp10w+IY2czHTQc=
+golang.org/x/tools v0.41.0/go.mod h1:XSY6eDqxVNiYgezAVqqCeihT4j1U2CCsqvH3WhQpnlg=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
 google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=

internal/cli/access.go

@@ -61,11 +61,8 @@ func (a *Access) Run(cli *CLI, version string) error {
 	}
 
 	wg := &sync.WaitGroup{}
-	wg.Add(2)
-
-	go func() {
-		defer wg.Done()
 
+	wg.Go(func() {
 		ip := a.PublicIPv4
 		if ip == nil {
 			ip = a.getIP(ntw, "tcp4")
@@ -76,11 +73,8 @@ func (a *Access) Run(cli *CLI, version string) error {
 		}
 
 		resp.IPv4 = a.makeURLs(conf, ip)
-	}()
+	})
-
+	wg.Go(func() {
-	go func() {
-		defer wg.Done()
-
 		ip := a.PublicIPv6
 		if ip == nil {
 			ip = a.getIP(ntw, "tcp6")
@@ -91,7 +85,7 @@ func (a *Access) Run(cli *CLI, version string) error {
 		}
 
 		resp.IPv6 = a.makeURLs(conf, ip)
-	}()
+	})
 
 	wg.Wait()
 

internal/cli/run_proxy.go

@@ -10,6 +10,7 @@ import (
 	"github.com/9seconds/mtg/v2/antireplay"
 	"github.com/9seconds/mtg/v2/events"
 	"github.com/9seconds/mtg/v2/internal/config"
+	"github.com/9seconds/mtg/v2/internal/proxyprotocol"
 	"github.com/9seconds/mtg/v2/internal/utils"
 	"github.com/9seconds/mtg/v2/ipblocklist"
 	"github.com/9seconds/mtg/v2/ipblocklist/files"
@@ -17,6 +18,7 @@ import (
 	"github.com/9seconds/mtg/v2/mtglib"
 	"github.com/9seconds/mtg/v2/network"
 	"github.com/9seconds/mtg/v2/stats"
+	"github.com/pires/go-proxyproto"
 	"github.com/rs/zerolog"
 	"github.com/yl2chen/cidranger"
 )
@@ -240,6 +242,14 @@ func runProxy(conf *config.Config, version string) error { //nolint: funlen
 		return fmt.Errorf("cannot build ip allowlist: %w", err)
 	}
 
+	dcOverrides := map[int][]string{}
+	for _, override := range conf.DCOverrides {
+		dcid := override.DC.Get()
+		for _, addr := range override.IPs {
+			dcOverrides[dcid] = append(dcOverrides[dcid], addr.Get(""))
+		}
+	}
+
 	opts := mtglib.ProxyOpts{
 		Logger:          logger,
 		Network:         ntw,
@@ -254,6 +264,7 @@ func runProxy(conf *config.Config, version string) error { //nolint: funlen
 
 		AllowFallbackOnUnknownDC: conf.AllowFallbackOnUnknownDC.Get(false),
 		TolerateTimeSkewness:     conf.TolerateTimeSkewness.Value,
+		DCOverrides:              dcOverrides,
 	}
 
 	proxy, err := mtglib.NewProxy(opts)
@@ -266,6 +277,14 @@ func runProxy(conf *config.Config, version string) error { //nolint: funlen
 		return fmt.Errorf("cannot start proxy: %w", err)
 	}
 
+	if conf.ProxyProtocolListener.Get(false) {
+		listener = &proxyprotocol.ListenerAdapter{
+			Listener: proxyproto.Listener{
+				Listener: listener,
+			},
+		}
+	}
+
 	ctx := utils.RootContext()
 
 	go proxy.Serve(listener) //nolint: errcheck

internal/cli/simple_run.go

@@ -18,7 +18,7 @@ type SimpleRun struct {
 	TCPBuffer           string        `kong:"name='tcp-buffer',short='b',default='4KB',help='Deprecated and ignored'"`                                                 //nolint: lll
 	PreferIP            string        `kong:"name='prefer-ip',short='i',default='prefer-ipv6',help='IP preference. By default we prefer IPv6 with fallback to IPv4.'"` //nolint: lll
 	DomainFrontingPort  uint64        `kong:"name='domain-fronting-port',short='p',default='443',help='A port to access for domain fronting.'"`                        //nolint: lll
-	DOHIP               net.IP        `kong:"name='doh-ip',short='n',default='9.9.9.9',help='IP address of DNS-over-HTTP to use.'"`                                    //nolint: lll
+	DOHIP               net.IP        `kong:"name='doh-ip',short='n',default='1.1.1.1',help='IP address of DNS-over-HTTP to use.'"`                                    //nolint: lll
 	Timeout             time.Duration `kong:"name='timeout',short='t',default='10s',help='Network timeout to use'"`                                                    //nolint: lll
 	Socks5Proxies       []string      `kong:"name='socks5-proxy',short='s',help='Socks5 proxies to use for network access.'"`                                          //nolint: lll
 	AntiReplayCacheSize string        `kong:"name='antireplay-cache-size',short='a',default='1MB',help='A size of anti-replay cache to use.'"`                         //nolint: lll

internal/config/config.go

@@ -25,6 +25,7 @@ type Config struct {
 	AllowFallbackOnUnknownDC TypeBool        `json:"allowFallbackOnUnknownDc"`
 	Secret                   mtglib.Secret   `json:"secret"`
 	BindTo                   TypeHostPort    `json:"bindTo"`
+	ProxyProtocolListener    TypeBool        `json:"proxyProtocolListener"`
 	PreferIP                 TypePreferIP    `json:"preferIp"`
 	DomainFrontingPort       TypePort        `json:"domainFrontingPort"`
 	TolerateTimeSkewness     TypeDuration    `json:"tolerateTimeSkewness"`
@@ -64,6 +65,10 @@ type Config struct {
 			MetricPrefix TypeMetricPrefix `json:"metricPrefix"`
 		} `json:"prometheus"`
 	} `json:"stats"`
+	DCOverrides []struct {
+		DC  TypeDC         `json:"dc"`
+		IPs []TypeHostPort `json:"ips"`
+	} `json:"dcOverrides"`
 }
 
 func (c *Config) Validate() error {

internal/config/parse.go

@@ -5,7 +5,7 @@ import (
 	"encoding/json"
 	"fmt"
 
-	"github.com/pelletier/go-toml"
+	"github.com/pelletier/go-toml/v2"
 )
 
 type tomlConfig struct {
@@ -13,6 +13,7 @@ type tomlConfig struct {
 	AllowFallbackOnUnknownDC bool   `toml:"allow-fallback-on-unknown-dc" json:"allowFallbackOnUnknownDc,omitempty"`
 	Secret                   string `toml:"secret" json:"secret"`
 	BindTo                   string `toml:"bind-to" json:"bindTo"`
+	ProxyProtocolListener    bool   `toml:"proxy-protocol-listener" json:"proxyProtocolListener"`
 	PreferIP                 string `toml:"prefer-ip" json:"preferIp,omitempty"`
 	DomainFrontingPort       uint   `toml:"domain-fronting-port" json:"domainFrontingPort,omitempty"`
 	TolerateTimeSkewness     string `toml:"tolerate-time-skewness" json:"tolerateTimeSkewness,omitempty"`
@@ -59,6 +60,10 @@ type tomlConfig struct {
 			MetricPrefix string `toml:"metric-prefix" json:"metricPrefix,omitempty"`
 		} `toml:"prometheus" json:"prometheus,omitempty"`
 	} `toml:"stats" json:"stats,omitempty"`
+	DCOverrides []struct {
+		DC  uint     `toml:"dc" json:"dc"`
+		IPs []string `toml:"ips" json:"ips"`
+	} `toml:"dc-overrides" json:"dcOverrides,omitempty"`
 }
 
 func Parse(rawData []byte) (*Config, error) {

internal/config/type_bool_test.go

@@ -20,7 +20,7 @@ type TypeBoolTestSuite struct {
 }
 
 func (suite *TypeBoolTestSuite) TestUnmarshalFail() {
-	testData := []interface{}{
+	testData := []any{
 		"",
 		"np",
 		"нет",
@@ -29,7 +29,7 @@ func (suite *TypeBoolTestSuite) TestUnmarshalFail() {
 	}
 
 	for _, v := range testData {
-		data, err := json.Marshal(map[string]interface{}{
+		data, err := json.Marshal(map[string]any{
 			"value": v,
 		})
 		suite.NoError(err)

internal/config/type_dc.go

@@ -0,0 +1,41 @@
+package config
+
+import (
+	"fmt"
+	"strconv"
+)
+
+type TypeDC struct {
+	Value int
+}
+
+func (t *TypeDC) Set(value string) error {
+	parsed, err := strconv.ParseInt(value, 10, 16)
+	if err != nil {
+		return fmt.Errorf("cannot parse dc: %w", err)
+	}
+
+	if parsed < 0 {
+		parsed = -parsed
+	}
+
+	t.Value = int(parsed)
+
+	return nil
+}
+
+func (t *TypeDC) UnmarshalJSON(data []byte) error {
+	return t.Set(string(data))
+}
+
+func (t TypeDC) MarshalJSON() ([]byte, error) {
+	return []byte(t.String()), nil
+}
+
+func (t TypeDC) String() string {
+	return strconv.Itoa(t.Value)
+}
+
+func (t TypeDC) Get() int {
+	return t.Value
+}

internal/config/type_dc_test.go

@@ -0,0 +1,96 @@
+package config_test
+
+import (
+	"encoding/json"
+	"strconv"
+	"testing"
+
+	"github.com/9seconds/mtg/v2/internal/config"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/suite"
+)
+
+type typeDCTestStruct struct {
+	Value config.TypeDC `json:"value"`
+}
+
+type TypeDCTestSuite struct {
+	suite.Suite
+}
+
+func (suite *TypeDCTestSuite) TestUnmarshalFail() {
+	testData := []string{
+		"-1s",
+		"1202002020202",
+		"xxx",
+		"-11111111111111",
+		"",
+	}
+
+	for _, v := range testData {
+		data, err := json.Marshal(map[string]string{
+			"value": v,
+		})
+		suite.NoError(err)
+
+		suite.T().Run(v, func(t *testing.T) {
+			assert.Error(t, json.Unmarshal(data, &typeDCTestStruct{}))
+		})
+	}
+}
+
+func (suite *TypeDCTestSuite) TestUnmarshalOk() {
+	testData := map[int]int{
+		1:   1,
+		-1:  1,
+		203: 203,
+	}
+
+	for value, expected := range testData {
+		data, err := json.Marshal(map[string]int{
+			"value": value,
+		})
+		suite.NoError(err)
+
+		suite.T().Run(strconv.Itoa(value), func(t *testing.T) {
+			testStruct := &typeDCTestStruct{}
+
+			assert.NoError(t, json.Unmarshal(data, testStruct))
+			assert.Equal(t, expected, testStruct.Value.Value)
+			assert.Equal(t, expected, testStruct.Value.Get())
+		})
+	}
+}
+
+func (suite *TypeDCTestSuite) TestMarshalOk() {
+	testData := map[string]int{
+		"1":   1,
+		"203": 203,
+	}
+
+	for k, v := range testData {
+		value := k
+		expected := v
+
+		suite.T().Run(value, func(t *testing.T) {
+			testStruct := &typeDCTestStruct{}
+
+			assert.NoError(t, testStruct.Value.Set(value))
+
+			data, err := json.Marshal(testStruct)
+			assert.NoError(t, err)
+
+			expectedJSON, err := json.Marshal(map[string]int{
+				"value": expected,
+			})
+			assert.NoError(t, err)
+
+			assert.JSONEq(t, string(expectedJSON), string(data))
+		})
+	}
+}
+
+func TestTypeDC(t *testing.T) {
+	t.Parallel()
+	suite.Run(t, &TypeDCTestSuite{})
+}

internal/proxyprotocol/adapter.go

@@ -0,0 +1,20 @@
+package proxyprotocol
+
+import (
+	"net"
+
+	"github.com/pires/go-proxyproto"
+)
+
+type ListenerAdapter struct {
+	proxyproto.Listener
+}
+
+func (l *ListenerAdapter) Accept() (net.Conn, error) {
+	conn, err := l.Listener.Accept()
+	if err != nil {
+		return nil, err
+	}
+
+	return connWrapper{conn.(*proxyproto.Conn)}, nil
+}

internal/proxyprotocol/conn.go

@@ -0,0 +1,25 @@
+package proxyprotocol
+
+import "github.com/pires/go-proxyproto"
+
+type connWrapper struct {
+	*proxyproto.Conn
+}
+
+func (c connWrapper) CloseRead() error {
+	tcpConn, ok := c.TCPConn()
+	if !ok {
+		panic("we support only tcp connections")
+	}
+
+	return tcpConn.CloseRead()
+}
+
+func (c connWrapper) CloseWrite() error {
+	tcpConn, ok := c.TCPConn()
+	if !ok {
+		panic("we support only tcp connections")
+	}
+
+	return tcpConn.CloseWrite()
+}

ipblocklist/firehol.go

@@ -112,18 +112,15 @@ func (f *Firehol) update() {
 	defer cancel()
 
 	wg := &sync.WaitGroup{}
-	wg.Add(len(f.blocklists))
 
 	mutex := &sync.Mutex{}
 	ranger := cidranger.NewPCTrieRanger()
 
 	for _, v := range f.blocklists {
-		go func(file files.File) {
+		wg.Go(func() {
-			defer wg.Done()
+			logger := f.logger.BindStr("filename", v.String())
 
-			logger := f.logger.BindStr("filename", file.String())
+			fileContent, err := v.Open(ctx)
-
-			fileContent, err := file.Open(ctx)
 			if err != nil {
 				logger.WarningError("update has failed", err)
 
@@ -135,7 +132,7 @@ func (f *Firehol) update() {
 			if err := f.updateFromFile(mutex, ranger, bufio.NewScanner(fileContent)); err != nil {
 				logger.WarningError("update has failed", err)
 			}
-		}(v)
+		})
 	}
 
 	wg.Wait()

logger/init.go

@@ -8,5 +8,5 @@ package logger
 // commonly used by many 3pp tools. While mtglib itself does not need it, it is
 // always a good idea to support it and have a transient end to end logging.
 type StdLikeLogger interface {
-	Printf(format string, args ...interface{})
+	Printf(format string, args ...any)
 }

logger/noop.go

@@ -8,7 +8,7 @@ func (n noopLogger) Named(_ string) mtglib.Logger          { return n }
 func (n noopLogger) BindInt(_ string, _ int) mtglib.Logger { return n }
 func (n noopLogger) BindStr(_, _ string) mtglib.Logger     { return n }
 func (n noopLogger) BindJSON(_, _ string) mtglib.Logger    { return n }
-func (n noopLogger) Printf(_ string, _ ...interface{})     {}
+func (n noopLogger) Printf(_ string, _ ...any)             {}
 func (n noopLogger) Info(_ string)                         {}
 func (n noopLogger) Warning(_ string)                      {}
 func (n noopLogger) Debug(_ string)                        {}

logger/zerolog.go

@@ -78,7 +78,7 @@ func (z *zeroLogContext) BindJSON(name, value string) mtglib.Logger {
 	}
 }
 
-func (z *zeroLogContext) Printf(format string, args ...interface{}) {
+func (z *zeroLogContext) Printf(format string, args ...any) {
 	z.Debug(fmt.Sprintf(format, args...))
 }
 

mise.lock

@@ -0,0 +1,38 @@
+[[tools.go]]
+version = "1.26.0"
+backend = "core:go"
+"platforms.linux-arm64" = { checksum = "sha256:bd03b743eb6eb4193ea3c3fd3956546bf0e3ca5b7076c8226334afe6b75704cd", url = "https://dl.google.com/go/go1.26.0.linux-arm64.tar.gz"}
+"platforms.linux-x64" = { checksum = "sha256:aac1b08a0fb0c4e0a7c1555beb7b59180b05dfc5a3d62e40e9de90cd42f88235", url = "https://dl.google.com/go/go1.26.0.linux-amd64.tar.gz"}
+"platforms.macos-arm64" = { checksum = "sha256:b1640525dfe68f066d56f200bef7bf4dce955a1a893bd061de6754c211431023", url = "https://dl.google.com/go/go1.26.0.darwin-arm64.tar.gz"}
+"platforms.macos-x64" = { checksum = "sha256:1ca28b7703cbea05a65b2a1d92d6b308610ef92f8824578a0874f2e60c9d5a22", url = "https://dl.google.com/go/go1.26.0.darwin-amd64.tar.gz"}
+"platforms.windows-x64" = { checksum = "sha256:9bbe0fc64236b2b51f6255c05c4232532b8ecc0e6d2e00950bd3021d8a4d07d4", url = "https://dl.google.com/go/go1.26.0.windows-amd64.zip"}
+
+[[tools."go:golang.org/x/pkgsite/cmd/pkgsite"]]
+version = "latest"
+backend = "go:golang.org/x/pkgsite/cmd/pkgsite"
+
+[[tools."go:golang.org/x/tools/gopls"]]
+version = "0.21.1"
+backend = "go:golang.org/x/tools/gopls"
+
+[[tools."go:mvdan.cc/gofumpt"]]
+version = "0.9.2"
+backend = "go:mvdan.cc/gofumpt"
+
+[[tools.golangci-lint]]
+version = "2.10.1"
+backend = "aqua:golangci/golangci-lint"
+"platforms.linux-arm64" = { checksum = "sha256:6652b42ae02915eb2f9cb2a2e0cac99514c8eded8388d88ae3e06e1a52c00de8", url = "https://github.com/golangci/golangci-lint/releases/download/v2.10.1/golangci-lint-2.10.1-linux-arm64.tar.gz"}
+"platforms.linux-x64" = { checksum = "sha256:dfa775874cf0561b404a02a8f4481fc69b28091da95aa697259820d429b09c99", url = "https://github.com/golangci/golangci-lint/releases/download/v2.10.1/golangci-lint-2.10.1-linux-amd64.tar.gz"}
+"platforms.macos-arm64" = { checksum = "sha256:03bfadf67e52b441b7ec21305e501c717df93c959836d66c7f97312654acb297", url = "https://github.com/golangci/golangci-lint/releases/download/v2.10.1/golangci-lint-2.10.1-darwin-arm64.tar.gz"}
+"platforms.macos-x64" = { checksum = "sha256:66fb0da81b8033b477f97eea420d4b46b230ca172b8bb87c6610109f3772b6b6", url = "https://github.com/golangci/golangci-lint/releases/download/v2.10.1/golangci-lint-2.10.1-darwin-amd64.tar.gz"}
+"platforms.windows-x64" = { checksum = "sha256:c60c87695e79db8e320f0e5be885059859de52bb5ee5f11be5577828570bc2a3", url = "https://github.com/golangci/golangci-lint/releases/download/v2.10.1/golangci-lint-2.10.1-windows-amd64.zip"}
+
+[[tools.goreleaser]]
+version = "2.13.3"
+backend = "aqua:goreleaser/goreleaser"
+"platforms.linux-arm64" = { checksum = "sha256:156656d0f874542d618568bd50afd3d33ced2e8aab2c60cc7c21e1b9fa52031e", url = "https://github.com/goreleaser/goreleaser/releases/download/v2.13.3/goreleaser_Linux_arm64.tar.gz"}
+"platforms.linux-x64" = { checksum = "sha256:4b66f2f78f78561330350651ade557b70328664718490f37834749073af21d20", url = "https://github.com/goreleaser/goreleaser/releases/download/v2.13.3/goreleaser_Linux_x86_64.tar.gz"}
+"platforms.macos-arm64" = { checksum = "sha256:5516c37779efb3935d5b213cda3b0b9025ae94ddbcb51df6919acbcdef4194b0", url = "https://github.com/goreleaser/goreleaser/releases/download/v2.13.3/goreleaser_Darwin_all.tar.gz"}
+"platforms.macos-x64" = { checksum = "sha256:5516c37779efb3935d5b213cda3b0b9025ae94ddbcb51df6919acbcdef4194b0", url = "https://github.com/goreleaser/goreleaser/releases/download/v2.13.3/goreleaser_Darwin_all.tar.gz"}
+"platforms.windows-x64" = { checksum = "sha256:c5586c4ed749ca358ad61ed73ee4b8039cfa68daae8c23e69fb086d549dfb31d", url = "https://github.com/goreleaser/goreleaser/releases/download/v2.13.3/goreleaser_Windows_x86_64.zip"}

mtglib/init.go

@@ -249,7 +249,7 @@ type Logger interface {
 	BindJSON(name, value string) Logger
 
 	// Printf is to support log.Logger behavior.
-	Printf(format string, args ...interface{})
+	Printf(format string, args ...any)
 
 	// Info puts a message about some normal situation.
 	Info(msg string)

mtglib/init_internal_test.go

@@ -12,7 +12,7 @@ func (n NoopLogger) Named(_ string) Logger             { return n }
 func (n NoopLogger) BindInt(_ string, _ int) Logger { return n }
 func (n NoopLogger) BindStr(_, _ string) Logger     { return n }
 func (n NoopLogger) BindJSON(_, _ string) Logger    { return n }
-func (n NoopLogger) Printf(_ string, _ ...interface{}) {}
+func (n NoopLogger) Printf(_ string, _ ...any)      {}
 func (n NoopLogger) Info(_ string)                  {}
 func (n NoopLogger) Warning(_ string)               {}
 func (n NoopLogger) Debug(_ string)                 {}

mtglib/internal/dc/addr.go

@@ -0,0 +1,10 @@
+package dc
+
+type Addr struct {
+	Network string
+	Address string
+}
+
+func (d Addr) String() string {
+	return d.Address
+}

mtglib/internal/dc/addr_set.go

@@ -0,0 +1,33 @@
+package dc
+
+import "math/rand/v2"
+
+type dcAddrSet struct {
+	v4 map[int][]Addr
+	v6 map[int][]Addr
+}
+
+func (d dcAddrSet) getV4(dc int) []Addr {
+	if d.v4 == nil {
+		return nil
+	}
+	return d.get(d.v4[dc])
+}
+
+func (d dcAddrSet) getV6(dc int) []Addr {
+	if d.v6 == nil {
+		return nil
+	}
+	return d.get(d.v6[dc])
+}
+
+func (d dcAddrSet) get(addrs []Addr) []Addr {
+	otherSet := make([]Addr, 0, len(addrs))
+	otherSet = append(otherSet, addrs...)
+
+	rand.Shuffle(len(otherSet), func(i, j int) {
+		otherSet[i], otherSet[j] = otherSet[j], otherSet[i]
+	})
+
+	return otherSet
+}

mtglib/internal/dc/addr_test.go

@@ -0,0 +1,16 @@
+package dc_test
+
+import (
+	"testing"
+
+	"github.com/9seconds/mtg/v2/mtglib/internal/dc"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestAddr(t *testing.T) {
+	t.Parallel()
+
+	addr := dc.Addr{Network: "tcp4", Address: "127.0.0.1:443"}
+
+	assert.Equal(t, "127.0.0.1:443", addr.String())
+}

mtglib/internal/dc/init.go

@@ -0,0 +1,73 @@
+package dc
+
+type preferIP uint8
+
+const (
+	preferIPOnlyIPv4 preferIP = iota
+	preferIPOnlyIPv6
+	preferIPPreferIPv4
+	preferIPPreferIPv6
+)
+
+const (
+	DefaultDC = 2
+)
+
+type Logger interface {
+	Info(msg string)
+	WarningError(msg string, err error)
+}
+
+var (
+	// https://github.com/telegramdesktop/tdesktop/blob/master/Telegram/SourceFiles/mtproto/mtproto_dc_options.cpp#L30
+	defaultDCAddrSet = dcAddrSet{
+		v4: map[int][]Addr{
+			1: {
+				{Network: "tcp4", Address: "149.154.175.50:443"},
+			},
+			2: {
+				{Network: "tcp4", Address: "149.154.167.51:443"},
+				{Network: "tcp4", Address: "95.161.76.100:443"},
+			},
+			3: {
+				{Network: "tcp4", Address: "149.154.175.100:443"},
+			},
+			4: {
+				{Network: "tcp4", Address: "149.154.167.91:443"},
+			},
+			5: {
+				{Network: "tcp4", Address: "149.154.171.5:443"},
+			},
+		},
+		v6: map[int][]Addr{
+			1: {
+				{Network: "tcp6", Address: "[2001:b28:f23d:f001::a]:443"},
+			},
+			2: {
+				{Network: "tcp6", Address: "[2001:67c:04e8:f002::a]:443"},
+			},
+			3: {
+				{Network: "tcp6", Address: "[2001:b28:f23d:f003::a]:443"},
+			},
+			4: {
+				{Network: "tcp6", Address: "[2001:67c:04e8:f004::a]:443"},
+			},
+			5: {
+				{Network: "tcp6", Address: "[2001:b28:f23f:f005::a]:443"},
+			},
+		},
+	}
+
+	defaultDCOverridesAddrSet = dcAddrSet{
+		v4: map[int][]Addr{
+			203: {
+				{Network: "tcp4", Address: "91.105.192.100:443"},
+			},
+		},
+		v6: map[int][]Addr{
+			203: {
+				{Network: "tcp6", Address: "[2a0a:f280:0203:000a:5000:0000:0000:0100]:443"},
+			},
+		},
+	}
+)

mtglib/internal/dc/telegram.go

@@ -0,0 +1,79 @@
+package dc
+
+import (
+	"fmt"
+	"net"
+	"strings"
+)
+
+type Telegram struct {
+	view     dcView
+	preferIP preferIP
+}
+
+func (t *Telegram) GetAddresses(dc int) []Addr {
+	switch t.preferIP {
+	case preferIPOnlyIPv4:
+		return t.view.getV4(dc)
+	case preferIPOnlyIPv6:
+		return t.view.getV4(dc)
+	case preferIPPreferIPv4:
+		return append(t.view.getV4(dc), t.view.getV6(dc)...)
+	}
+
+	return append(t.view.getV6(dc), t.view.getV4(dc)...)
+}
+
+func New(ipPreference string, userOverrides map[int][]string) (*Telegram, error) {
+	var pref preferIP
+
+	switch strings.ToLower(ipPreference) {
+	case "prefer-ipv4":
+		pref = preferIPPreferIPv4
+	case "prefer-ipv6":
+		pref = preferIPPreferIPv6
+	case "only-ipv4":
+		pref = preferIPOnlyIPv4
+	case "only-ipv6":
+		pref = preferIPOnlyIPv6
+	default:
+		return nil, fmt.Errorf("unknown ip preference %s", ipPreference)
+	}
+
+	overrides := dcAddrSet{
+		v4: map[int][]Addr{},
+		v6: map[int][]Addr{},
+	}
+	for dc, addrs := range userOverrides {
+		for _, addr := range addrs {
+			host, _, err := net.SplitHostPort(addr)
+			if err != nil {
+				return nil, fmt.Errorf("incorrect host %s: %w", addr, err)
+			}
+
+			parsed := net.ParseIP(host)
+			if parsed == nil {
+				return nil, fmt.Errorf("incorrect host %s", addr)
+			}
+
+			if parsed.To4() != nil {
+				overrides.v4[dc] = append(overrides.v4[dc], Addr{
+					Network: "tcp4",
+					Address: addr,
+				})
+			} else {
+				overrides.v6[dc] = append(overrides.v6[dc], Addr{
+					Network: "tcp6",
+					Address: addr,
+				})
+			}
+		}
+	}
+
+	return &Telegram{
+		view: dcView{
+			overrides: overrides,
+		},
+		preferIP: pref,
+	}, nil
+}

mtglib/internal/dc/view.go

@@ -0,0 +1,21 @@
+package dc
+
+type dcView struct {
+	overrides dcAddrSet
+}
+
+func (d dcView) getV4(dc int) []Addr {
+	addrs := d.overrides.getV4(dc)
+	addrs = append(addrs, defaultDCOverridesAddrSet.getV4(dc)...)
+	addrs = append(addrs, defaultDCAddrSet.getV4(dc)...)
+
+	return addrs
+}
+
+func (d dcView) getV6(dc int) []Addr {
+	addrs := d.overrides.getV6(dc)
+	addrs = append(addrs, defaultDCOverridesAddrSet.getV6(dc)...)
+	addrs = append(addrs, defaultDCAddrSet.getV6(dc)...)
+
+	return addrs
+}

mtglib/internal/dc/view_test.go

@@ -0,0 +1,81 @@
+package dc
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/suite"
+)
+
+type ViewTestSuite struct {
+	suite.Suite
+
+	view dcView
+}
+
+func (suite *ViewTestSuite) SetupSuite() {
+	suite.view = dcView{
+		overrides: dcAddrSet{
+			v4: map[int][]Addr{
+				111: {
+					{Network: "tcp4", Address: "127.0.0.1:443"},
+				},
+				203: {
+					{Network: "tcp4", Address: "127.0.0.2:443"},
+				},
+			},
+			v6: map[int][]Addr{
+				203: {
+					{Network: "tcp6", Address: "xxx"},
+				},
+			},
+		},
+	}
+}
+
+func (suite *ViewTestSuite) TestGetV4() {
+	testData := map[int][]Addr{
+		111: {
+			{"tcp4", "127.0.0.1:443"},
+		},
+		203: {
+			{"tcp4", "127.0.0.2:443"},
+			{"tcp4", "91.105.192.100:443"},
+		},
+		2: {
+			{"tcp4", "149.154.167.51:443"},
+			{"tcp4", "95.161.76.100:443"},
+		},
+	}
+
+	for dc, addresses := range testData {
+		suite.T().Run(fmt.Sprintf("dc%d", dc), func(t *testing.T) {
+			assert.ElementsMatch(t, addresses, suite.view.getV4(dc))
+		})
+	}
+}
+
+func (suite *ViewTestSuite) TestGetV6() {
+	testData := map[int][]Addr{
+		111: {},
+		203: {
+			{"tcp6", "xxx"},
+			{"tcp6", "[2a0a:f280:0203:000a:5000:0000:0000:0100]:443"},
+		},
+		1: {
+			{"tcp6", "[2001:b28:f23d:f001::a]:443"},
+		},
+	}
+
+	for dc, addresses := range testData {
+		suite.T().Run(fmt.Sprintf("dc%d", dc), func(t *testing.T) {
+			assert.ElementsMatch(t, addresses, suite.view.getV6(dc))
+		})
+	}
+}
+
+func TestView(t *testing.T) {
+	t.Parallel()
+	suite.Run(t, &ViewTestSuite{})
+}

mtglib/internal/faketls/client_hello.go

@@ -76,7 +76,7 @@ func ParseClientHello(secret, handshake []byte) (ClientHello, error) {
 
 	computedRandom := mac.Sum(nil)
 
-	for i := 0; i < RandomLen; i++ {
+	for i := range RandomLen {
 		computedRandom[i] ^= hello.Random[i]
 	}
 

mtglib/internal/faketls/conn.go

@@ -3,7 +3,7 @@ package faketls
 import (
 	"bytes"
 	"fmt"
-	"math/rand"
+	"math/rand/v2"
 
 	"github.com/9seconds/mtg/v2/essentials"
 	"github.com/9seconds/mtg/v2/mtglib/internal/faketls/record"
@@ -53,7 +53,7 @@ func (c *Conn) Write(p []byte) (int, error) {
 	lenP := len(p)
 
 	for len(p) > 0 {
-		chunkSize := rand.Intn(record.TLSMaxRecordSize)
+		chunkSize := rand.IntN(record.TLSMaxRecordSize)
 		if chunkSize > len(p) || chunkSize == 0 {
 			chunkSize = len(p)
 		}

mtglib/internal/faketls/conn_test.go

@@ -2,9 +2,9 @@ package faketls_test
 
 import (
 	"bytes"
+	"crypto/rand"
 	"errors"
 	"io"
-	"math/rand"
 	"testing"
 
 	"github.com/9seconds/mtg/v2/internal/testlib"
@@ -123,7 +123,7 @@ func (suite *ConnTestSuite) TestWrite() {
 	suite.connMock.On("Write", mock.Anything).Return(0, nil)
 
 	dataToRec := make([]byte, record.TLSMaxRecordSize*2)
-	rand.Read(dataToRec) //nolint: staticcheck
+	rand.Read(dataToRec) //nolint: staticcheck, errcheck
 
 	n, err := suite.c.Write(dataToRec)
 	suite.NoError(err)

mtglib/internal/faketls/pools.go

@@ -6,7 +6,7 @@ import (
 )
 
 var bytesBufferPool = sync.Pool{
-	New: func() interface{} {
+	New: func() any {
 		return &bytes.Buffer{}
 	},
 }

mtglib/internal/faketls/record/pools.go

@@ -5,7 +5,7 @@ import (
 )
 
 var recordPool = sync.Pool{
-	New: func() interface{} {
+	New: func() any {
 		return &Record{}
 	},
 }

mtglib/internal/faketls/welcome.go

@@ -6,7 +6,7 @@ import (
 	"crypto/sha256"
 	"encoding/binary"
 	"io"
-	mrand "math/rand"
+	mrand "math/rand/v2"
 
 	"github.com/9seconds/mtg/v2/mtglib/internal/faketls/record"
 	"golang.org/x/crypto/curve25519"
@@ -36,7 +36,7 @@ func SendWelcomePacket(writer io.Writer, secret []byte, clientHello ClientHello)
 	rec.Type = record.TypeApplicationData
 	rec.Version = record.Version12
 
-	if _, err := io.CopyN(&rec.Payload, rand.Reader, int64(1024+mrand.Intn(3092))); err != nil {
+	if _, err := io.CopyN(&rec.Payload, rand.Reader, int64(1024+mrand.IntN(3092))); err != nil {
 		panic(err)
 	}
 

mtglib/internal/faketls/welcome_test.go

@@ -3,8 +3,8 @@ package faketls_test
 import (
 	"bytes"
 	"crypto/hmac"
+	"crypto/rand"
 	"crypto/sha256"
-	"math/rand"
 	"testing"
 	"time"
 

mtglib/internal/obfuscated2/handshake_frame.go

@@ -63,7 +63,7 @@ func (h *handshakeFrame) connectionType() []byte {
 func (h *handshakeFrame) invert() handshakeFrame {
 	copyFrame := *h
 
-	for i := 0; i < handshakeFrameLenKey+handshakeFrameLenIV; i++ {
+	for i := range handshakeFrameLenKey + handshakeFrameLenIV {
 		copyFrame.data[handshakeFrameOffsetKey+i] = h.data[handshakeFrameOffsetConnectionType-1-i]
 	}
 

mtglib/internal/obfuscated2/init_test.go

@@ -117,7 +117,7 @@ func NewServerHandshakeTestData(t *testing.T) ServerHandshakeTestData {
 
 	serverEncryptedReverted := make([]byte, len(serverEncrypted))
 
-	for i := 0; i < 32+16; i++ {
+	for i := range 32 + 16 {
 		serverEncryptedReverted[8+i] = serverEncrypted[8+32+16-1-i]
 	}
 

mtglib/internal/obfuscated2/pools.go

@@ -9,12 +9,12 @@ import (
 
 var (
 	sha256HasherPool = sync.Pool{
-		New: func() interface{} {
+		New: func() any {
 			return sha256.New()
 		},
 	}
 	bytesBufferPool = sync.Pool{
-		New: func() interface{} {
+		New: func() any {
 			return &bytes.Buffer{}
 		},
 	}

mtglib/internal/relay/init.go

@@ -5,5 +5,5 @@ const (
 )
 
 type Logger interface {
-	Printf(msg string, args ...interface{})
+	Printf(msg string, args ...any)
 }

mtglib/internal/relay/init_test.go

@@ -2,4 +2,4 @@ package relay_test
 
 type loggerMock struct{}
 
-func (l loggerMock) Printf(format string, args ...interface{}) {}
+func (l loggerMock) Printf(format string, args ...any) {}

mtglib/internal/relay/pools.go

@@ -3,7 +3,7 @@ package relay
 import "sync"
 
 var copyBufferPool = sync.Pool{
-	New: func() interface{} {
+	New: func() any {
 		rv := make([]byte, copyBufferSize)
 
 		return &rv

mtglib/internal/telegram/address_pool.go

@@ -1,41 +0,0 @@
-package telegram
-
-import "math/rand"
-
-type addressPool struct {
-	v4 [][]tgAddr
-	v6 [][]tgAddr
-}
-
-func (a addressPool) isValidDC(dc int) bool {
-	return dc > 0 && dc <= len(a.v4) && dc <= len(a.v6)
-}
-
-func (a addressPool) getRandomDC() int {
-	return 1 + rand.Intn(len(a.v4))
-}
-
-func (a addressPool) getV4(dc int) []tgAddr {
-	return a.get(a.v4, dc-1)
-}
-
-func (a addressPool) getV6(dc int) []tgAddr {
-	return a.get(a.v6, dc-1)
-}
-
-func (a addressPool) get(addresses [][]tgAddr, dc int) []tgAddr {
-	if dc < 0 || dc >= len(addresses) {
-		return nil
-	}
-
-	rv := make([]tgAddr, len(addresses[dc]))
-	copy(rv, addresses[dc])
-
-	if len(rv) > 1 {
-		rand.Shuffle(len(rv), func(i, j int) {
-			rv[i], rv[j] = rv[j], rv[i]
-		})
-	}
-
-	return rv
-}

mtglib/internal/telegram/init.go

@@ -1,90 +0,0 @@
-package telegram
-
-import (
-	"context"
-	"errors"
-
-	"github.com/9seconds/mtg/v2/essentials"
-)
-
-var errNoAddresses = errors.New("no addresses")
-
-type preferIP uint8
-
-const (
-	preferIPOnlyIPv4 preferIP = iota
-	preferIPOnlyIPv6
-	preferIPPreferIPv4
-	preferIPPreferIPv6
-)
-
-type tgAddr struct {
-	network string
-	address string
-}
-
-// https://github.com/telegramdesktop/tdesktop/blob/master/Telegram/SourceFiles/mtproto/mtproto_dc_options.cpp#L30
-var (
-	productionV4Addresses = [][]tgAddr{
-		{ // dc1
-			{network: "tcp4", address: "149.154.175.50:443"},
-		},
-		{ // dc2
-			{network: "tcp4", address: "149.154.167.51:443"},
-			{network: "tcp4", address: "95.161.76.100:443"},
-		},
-		{ // dc3
-			{network: "tcp4", address: "149.154.175.100:443"},
-		},
-		{ // dc4
-			{network: "tcp4", address: "149.154.167.91:443"},
-		},
-		{ // dc5
-			{network: "tcp4", address: "149.154.171.5:443"},
-		},
-	}
-	productionV6Addresses = [][]tgAddr{
-		{ // dc1
-			{network: "tcp6", address: "[2001:b28:f23d:f001::a]:443"},
-		},
-		{ // dc2
-			{network: "tcp6", address: "[2001:67c:04e8:f002::a]:443"},
-		},
-		{ // dc3
-			{network: "tcp6", address: "[2001:b28:f23d:f003::a]:443"},
-		},
-		{ // dc4
-			{network: "tcp6", address: "[2001:67c:04e8:f004::a]:443"},
-		},
-		{ // dc5
-			{network: "tcp6", address: "[2001:b28:f23f:f005::a]:443"},
-		},
-	}
-
-	testV4Addresses = [][]tgAddr{
-		{ // dc1
-			{network: "tcp4", address: "149.154.175.10:443"},
-		},
-		{ // dc2
-			{network: "tcp4", address: "149.154.167.40:443"},
-		},
-		{ // dc3
-			{network: "tcp4", address: "149.154.175.117:443"},
-		},
-	}
-	testV6Addresses = [][]tgAddr{
-		{ // dc1
-			{network: "tcp6", address: "[2001:b28:f23d:f001::e]:443"},
-		},
-		{ // dc2
-			{network: "tcp6", address: "[2001:67c:04e8:f002::e]:443"},
-		},
-		{ // dc3
-			{network: "tcp6", address: "[2001:b28:f23d:f003::e]:443"},
-		},
-	}
-)
-
-type Dialer interface {
-	DialContext(ctx context.Context, network, address string) (essentials.Conn, error)
-}

mtglib/internal/telegram/telegram.go

@@ -1,83 +0,0 @@
-package telegram
-
-import (
-	"context"
-	"fmt"
-	"strings"
-
-	"github.com/9seconds/mtg/v2/essentials"
-)
-
-type Telegram struct {
-	dialer   Dialer
-	preferIP preferIP
-	pool     addressPool
-}
-
-func (t Telegram) Dial(ctx context.Context, dc int) (essentials.Conn, error) {
-	var addresses []tgAddr
-
-	switch t.preferIP {
-	case preferIPOnlyIPv4:
-		addresses = t.pool.getV4(dc)
-	case preferIPOnlyIPv6:
-		addresses = t.pool.getV6(dc)
-	case preferIPPreferIPv4:
-		addresses = append(t.pool.getV4(dc), t.pool.getV6(dc)...)
-	case preferIPPreferIPv6:
-		addresses = append(t.pool.getV6(dc), t.pool.getV4(dc)...)
-	}
-
-	var conn essentials.Conn
-
-	err := errNoAddresses
-
-	for _, v := range addresses {
-		conn, err = t.dialer.DialContext(ctx, v.network, v.address)
-		if err == nil {
-			return conn, nil
-		}
-	}
-
-	return nil, fmt.Errorf("cannot dial to %d dc: %w", dc, err)
-}
-
-func (t Telegram) IsKnownDC(dc int) bool {
-	return t.pool.isValidDC(dc)
-}
-
-func (t Telegram) GetFallbackDC() int {
-	return t.pool.getRandomDC()
-}
-
-func New(dialer Dialer, ipPreference string, useTestDCs bool) (*Telegram, error) {
-	var pref preferIP
-
-	switch strings.ToLower(ipPreference) {
-	case "prefer-ipv4":
-		pref = preferIPPreferIPv4
-	case "prefer-ipv6":
-		pref = preferIPPreferIPv6
-	case "only-ipv4":
-		pref = preferIPOnlyIPv4
-	case "only-ipv6":
-		pref = preferIPOnlyIPv6
-	default:
-		return nil, fmt.Errorf("unknown ip preference %s", ipPreference)
-	}
-
-	pool := addressPool{
-		v4: productionV4Addresses,
-		v6: productionV6Addresses,
-	}
-	if useTestDCs {
-		pool.v4 = testV4Addresses
-		pool.v6 = testV6Addresses
-	}
-
-	return &Telegram{
-		dialer:   dialer,
-		preferIP: pref,
-		pool:     pool,
-	}, nil
-}

mtglib/internal/telegram/telegram_internal_test.go

@@ -1,159 +0,0 @@
-package telegram
-
-import (
-	"context"
-	"errors"
-	"io"
-	"net"
-	"strconv"
-	"testing"
-
-	"github.com/9seconds/mtg/v2/internal/testlib"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/mock"
-	"github.com/stretchr/testify/suite"
-)
-
-type TelegramTestSuite struct {
-	suite.Suite
-
-	dialerMock *testlib.MtglibNetworkMock
-	t          *Telegram
-}
-
-func (suite *TelegramTestSuite) SetupTest() {
-	suite.dialerMock = &testlib.MtglibNetworkMock{}
-	suite.t, _ = New(suite.dialerMock, "prefer-ipv4", false)
-}
-
-func (suite *TelegramTestSuite) TearDownTest() {
-	suite.dialerMock.AssertExpectations(suite.T())
-}
-
-func (suite *TelegramTestSuite) TestUnknownDC() {
-	testData := []int{
-		-1,
-		0,
-		6,
-		100,
-	}
-
-	for _, v := range testData {
-		value := v
-
-		suite.T().Run(strconv.Itoa(value), func(t *testing.T) {
-			_, err := suite.t.Dial(context.Background(), value)
-			assert.Error(t, err)
-			assert.False(t, suite.t.IsKnownDC(value))
-		})
-	}
-}
-
-func (suite *TelegramTestSuite) TestDialToCorrectIPs() {
-	testData := map[int][]tgAddr{}
-
-	for i := 1; i <= 5; i++ {
-		testData[i] = []tgAddr{}
-		testData[i] = append(testData[i], productionV4Addresses[i-1]...)
-		testData[i] = append(testData[i], productionV6Addresses[i-1]...)
-	}
-
-	for i, v := range testData {
-		idx := i
-		addresses := v
-
-		suite.T().Run(strconv.Itoa(idx), func(t *testing.T) {
-			for _, addr := range addresses {
-				suite.dialerMock.
-					On("DialContext", mock.Anything, addr.network, addr.address).
-					Once().
-					Return((*net.TCPConn)(nil), io.EOF)
-			}
-
-			_, err := suite.t.Dial(context.Background(), idx)
-			assert.True(t, errors.Is(err, io.EOF))
-			assert.True(t, suite.t.IsKnownDC(idx))
-		})
-	}
-}
-
-func (suite *TelegramTestSuite) TestDialPreferIPRange() {
-	testData := map[string][]tgAddr{
-		"prefer-ipv4": {testV4Addresses[0][0], testV6Addresses[0][0]},
-		"prefer-ipv6": {testV6Addresses[0][0], testV4Addresses[0][0]},
-		"only-ipv4":   {testV4Addresses[0][0]},
-		"only-ipv6":   {testV6Addresses[0][0]},
-	}
-
-	for k, v := range testData {
-		name := k
-		addresses := v
-
-		suite.T().Run(name, func(t *testing.T) {
-			for _, addr := range addresses {
-				suite.dialerMock.
-					On("DialContext", mock.Anything, addr.network, addr.address).
-					Once().
-					Return((*net.TCPConn)(nil), io.EOF)
-			}
-
-			tg, _ := New(suite.dialerMock, name, true)
-			_, err := tg.Dial(context.Background(), 1)
-
-			assert.True(t, errors.Is(err, io.EOF))
-		})
-	}
-}
-
-func (suite *TelegramTestSuite) TestDialPreferIPPriority() {
-	testData := map[string]tgAddr{
-		"prefer-ipv4": productionV4Addresses[0][0],
-		"prefer-ipv6": productionV6Addresses[0][0],
-	}
-
-	for k, v := range testData {
-		name := k
-		addr := v
-
-		suite.T().Run(name, func(t *testing.T) {
-			conn := &net.TCPConn{}
-
-			suite.dialerMock.
-				On("DialContext", mock.Anything, addr.network, addr.address).
-				Once().
-				Return(conn, nil)
-
-			tg, _ := New(suite.dialerMock, name, false)
-
-			res, err := tg.Dial(context.Background(), 1)
-			assert.NoError(t, err)
-			assert.Equal(t, conn, res)
-		})
-	}
-}
-
-func (suite *TelegramTestSuite) TestUnknownPreferIP() {
-	_, err := New(suite.dialerMock, "xxx", false)
-	suite.Error(err)
-}
-
-func (suite *TelegramTestSuite) TestFallbackDC() {
-	dcs := make([]int, 10)
-
-	for i := 0; i < len(dcs); i++ {
-		dcs[i] = suite.t.GetFallbackDC()
-	}
-
-	for _, v := range dcs {
-		value := v
-
-		suite.T().Run(strconv.Itoa(value), func(t *testing.T) {
-			assert.True(t, suite.t.IsKnownDC(value))
-		})
-	}
-}
-
-func TestTelegram(t *testing.T) {
-	t.Parallel()
-	suite.Run(t, &TelegramTestSuite{})
-}

mtglib/proxy.go

@@ -10,11 +10,11 @@ import (
 	"time"
 
 	"github.com/9seconds/mtg/v2/essentials"
+	"github.com/9seconds/mtg/v2/mtglib/internal/dc"
 	"github.com/9seconds/mtg/v2/mtglib/internal/faketls"
 	"github.com/9seconds/mtg/v2/mtglib/internal/faketls/record"
 	"github.com/9seconds/mtg/v2/mtglib/internal/obfuscated2"
 	"github.com/9seconds/mtg/v2/mtglib/internal/relay"
-	"github.com/9seconds/mtg/v2/mtglib/internal/telegram"
 	"github.com/panjf2000/ants/v2"
 )
 
@@ -28,7 +28,7 @@ type Proxy struct {
 	tolerateTimeSkewness     time.Duration
 	domainFrontingPort       int
 	workerPool               *ants.PoolWithFunc
-	telegram                 *telegram.Telegram
+	telegram                 *dc.Telegram
 
 	secret          Secret
 	network         Network
@@ -219,18 +219,26 @@ func (p *Proxy) doObfuscated2Handshake(ctx *streamContext) error {
 }
 
 func (p *Proxy) doTelegramCall(ctx *streamContext) error {
-	dc := ctx.dc
+	dcid := ctx.dc
-
-	if p.allowFallbackOnUnknownDC && !p.telegram.IsKnownDC(dc) {
-		dc = p.telegram.GetFallbackDC()
-		ctx.logger = ctx.logger.BindInt("fallback_dc", dc)
 
+	addresses := p.telegram.GetAddresses(dcid)
+	if len(addresses) == 0 && p.allowFallbackOnUnknownDC {
+		ctx.logger = ctx.logger.BindInt("fallback_dc", dc.DefaultDC)
 		ctx.logger.Warning("unknown DC, fallbacks")
+		addresses = p.telegram.GetAddresses(dc.DefaultDC)
 	}
 
-	conn, err := p.telegram.Dial(ctx, dc)
+	var conn essentials.Conn
+	var err error
+
+	for _, addr := range addresses {
+		conn, err = p.network.Dial(addr.Network, addr.Address)
+		if err == nil {
+			break
+		}
+	}
 	if err != nil {
-		return fmt.Errorf("cannot dial to Telegram: %w", err)
+		return fmt.Errorf("no addresses to call: %w", err)
 	}
 
 	encryptor, decryptor, err := obfuscated2.ServerHandshake(conn)
@@ -292,9 +300,9 @@ func NewProxy(opts ProxyOpts) (*Proxy, error) {
 		return nil, fmt.Errorf("invalid settings: %w", err)
 	}
 
-	tg, err := telegram.New(opts.Network, opts.getPreferIP(), opts.UseTestDCs)
+	tg, err := dc.New(opts.getPreferIP(), opts.DCOverrides)
 	if err != nil {
-		return nil, fmt.Errorf("cannot build telegram dialer: %w", err)
+		return nil, fmt.Errorf("cannot build telegram dc fetcher: %w", err)
 	}
 
 	ctx, cancel := context.WithCancel(context.Background())
@@ -315,7 +323,7 @@ func NewProxy(opts ProxyOpts) (*Proxy, error) {
 	}
 
 	pool, err := ants.NewPoolWithFunc(opts.getConcurrency(),
-		func(arg interface{}) {
+		func(arg any) {
 			proxy.ServeConn(arg.(essentials.Conn)) //nolint: forcetypeassert
 		},
 		ants.WithLogger(opts.getLogger("ants")),

mtglib/proxy_opts.go

@@ -110,7 +110,15 @@ type ProxyOpts struct {
 	// Telegram-related projects.
 	//
 	// This is an optional setting.
+	//
+	// OBSOLETE and DEPRECATED. Ignored.
 	UseTestDCs bool
+
+	// DCOverrides defines a set of IP addresses that should be used
+	// with a higher priority to those that are calculated somehow by mtg.
+	//
+	// This is an optional setting
+	DCOverrides map[int][]string
 }
 
 func (p ProxyOpts) valid() error {

mtglib/stream_context.go

@@ -32,7 +32,7 @@ func (s *streamContext) Err() error {
 	return s.ctx.Err() //nolint: wrapcheck
 }
 
-func (s *streamContext) Value(key interface{}) interface{} {
+func (s *streamContext) Value(key any) any {
 	return s.ctx.Value(key)
 }
 

network/circuit_breaker_internal_test.go

@@ -52,17 +52,9 @@ func (suite *CircuitBreakerTestSuite) TestMultipleRunsOk() {
 		Return(suite.connMock, nil)
 
 	wg := &sync.WaitGroup{}
-	wg.Add(5)
-
-	go func() {
-		wg.Wait()
-		suite.ctxCancel()
-	}()
-
-	for i := 0; i < 5; i++ {
-		go func() {
-			defer wg.Done()
 
+	for range 5 {
+		wg.Go(func() {
 			conn, err := suite.d.DialContext(suite.ctx, "tcp", "127.0.0.1")
 
 			suite.mutex.Lock()
@@ -70,9 +62,14 @@ func (suite *CircuitBreakerTestSuite) TestMultipleRunsOk() {
 
 			suite.NoError(err)
 			suite.Equal("127.0.0.1:3128", conn.RemoteAddr().String())
-		}()
+		})
 	}
 
+	go func() {
+		wg.Wait()
+		suite.ctxCancel()
+	}()
+
 	suite.Eventually(func() bool {
 		_, ok := <-suite.ctx.Done()
 

network/init.go

@@ -63,7 +63,7 @@ const (
 	// DefaultDOHHostname defines a default IP address for DOH host. Since mtg is
 	// simple, please pass IP address here. We do not have bootstrap servers here
 	// embedded.
-	DefaultDOHHostname = "9.9.9.9"
+	DefaultDOHHostname = "1.1.1.1"
 
 	// DNSTimeout defines a timeout for DNS queries.
 	DNSTimeout = 5 * time.Second

network/load_balanced_socks5.go

@@ -3,7 +3,7 @@ package network
 import (
 	"context"
 	"fmt"
-	"math/rand"
+	"math/rand/v2"
 	"net/url"
 
 	"github.com/9seconds/mtg/v2/essentials"
@@ -19,7 +19,7 @@ func (l loadBalancedSocks5Dialer) Dial(network, address string) (essentials.Conn
 
 func (l loadBalancedSocks5Dialer) DialContext(ctx context.Context, network, address string) (essentials.Conn, error) {
 	length := len(l.dialers)
-	start := rand.Intn(length)
+	start := rand.IntN(length)
 	moved := false
 
 	for i := start; i != start || !moved; i = (i + 1) % length {

network/load_balanced_socks5_test.go

@@ -64,7 +64,7 @@ func (suite *LoadBalancedSocks5TestSuite) TestCannotDial() {
 	})
 	suite.NoError(err)
 
-	for i := 0; i < network.ProxyDialerOpenThreshold*2; i++ {
+	for range network.ProxyDialerOpenThreshold * 2 {
 		_, err = lbDialer.Dial("tcp", "127.1.1.1:80")
 		suite.True(errors.Is(err, network.ErrCannotDialWithAllProxies))
 	}

network/network.go

@@ -3,7 +3,7 @@ package network
 import (
 	"context"
 	"fmt"
-	"math/rand"
+	"math/rand/v2"
 	"net"
 	"net/http"
 	"sync"
@@ -81,32 +81,24 @@ func (n *network) dnsResolve(protocol, address string) ([]string, error) {
 
 	switch protocol {
 	case "tcp", "tcp4":
-		wg.Add(1)
+		wg.Go(func() {
-
-		go func() {
-			defer wg.Done()
-
 			resolved := n.dns.LookupA(address)
 
 			mutex.Lock()
 			ips = append(ips, resolved...)
 			mutex.Unlock()
-		}()
+		})
 	}
 
 	switch protocol {
 	case "tcp", "tcp6":
-		wg.Add(1)
+		wg.Go(func() {
-
-		go func() {
-			defer wg.Done()
-
 			resolved := n.dns.LookupAAAA(address)
 
 			mutex.Lock()
 			ips = append(ips, resolved...)
 			mutex.Unlock()
-		}()
+		})
 	}
 
 	wg.Wait()

stats/pools.go

@@ -3,7 +3,7 @@ package stats
 import "sync"
 
 var streamInfoPool = sync.Pool{
-	New: func() interface{} {
+	New: func() any {
 		return &streamInfo{
 			tags: make(map[string]string),
 		}